If an error is found (with a person of knowledge, a scholar or a student of knowledge), it is to be clarified with the evidence and dua for the author with ‘wafaqahu Allaah’ [may Allaah grant him success] or ‘saddada khata’ahu’ [may Allaah fill his mistake].
The like of these words are said as a rebuke and then the point of evidence is to be shown – ‘The evidence is such-and-such’; ‘He may have been unmindful of such-and-such’. They should clarify the matter with the scholars so they can clarify the mistakes to the person who made them.
If a plain error is found, and that individual is from the people of knowledge, it should be explained to them with the evidence in a good manner and with good speech – not with harshness and stringency, nor with announcing it, meaning that one says ‘It is not befitting to take knowledge from so-and-so’.
Rather, their mistake should be clarified while stating they are from the people of knowledge. They are to be taken from in that which they teach the people, except if the proof is established that they are incorrect.
Indeed, Maalik erred, Ahmad, Abu Haneefa, Shaa’fi’ee ath-Thawri and others. They have mistakes that are known, yet the masses are not prevented from taking from them in that which they were correct in.
There is no scholar except that they have issues in which they err – not understanding from the evidences that which others have and recant to that which is correct.